public class Student {
    public String studentName = "小明";
    private int classNumber = 1;
    private Student(String studentName,int classNumber){
        this.studentName = studentName;
        this.classNumber = classNumber;
        System.out.println("Student(studentName,classNumber)");
    }
    public Student(){
        System.out.println("学生姓名: "+studentName+" 班级: "+classNumber);
    }

    public void start(){
        System.out.println("上课了");
    }
    private void end(){
        System.out.println("下课了");
    }
    private void function(String str){
        System.out.println(str);
    }
}
